tips for preventing rust

6 Tips For Preventing Rust

Rust is the name for the orange-brown flakes of iron oxide that form on the surface of any metal containing iron that is exposed to air and water. It is a type of corrosion that can be highly destructive, as well as unsightly. In this article, we will share tips on how to prevent rust.

The rusting process begins when iron reacts with oxygen in the presence of water, saltwater, acids, or other harsh chemicals. As the iron oxide flakes off the metal surface, it exposes fresh iron molecules, which continue the reaction process. Eventually, large areas of rust form that may cause the entire metal structure to disintegrate.

A ferrous metal is one that contains iron and only iron can rust. Common ferrous metals include carbon steel (1018, 12L14), alloy steel (4130), and stainless steel (304, 316). Non-ferrous metals, such as aluminum and copper, contain little if any iron, and so cannot rust, though they can corrode.

Keep It Clean and Dry

Water is enemy number one when it comes to rust, because it’s the oxygen in water molecules that combines with iron to form iron oxide. That’s why metals left outdoors, such as cars, gates, or tanks, are more likely to rust. If the object is located in a humid indoors environment, such as a garage or basement, install a dehumidifier. Any type of mud or dirt adhered to the surface can hold water, so it’s important to keep metals clean.

Prevent Scratches

Scratches or cracks in the metal expose more metal and hold water, allowing it to remain in contact with the iron. This is why cold rolled steel is more corrosion resistant than hot rolled steel, because cold rolling creates a smoother surface without texture that can trap and hold water.

Apply A Protective Coating

Dipping metal objects, such as clocks, into a bluing solution of water, sodium hydroxide, and potassium nitrate, provides strong corrosion resistance. Commercially available rust prevention products in the form of aerosol sprays or cloth wipes also can protect metal objects, including tools, outdoor gear, vehicles, and large metal parts.

Use Stainless Steel

Stainless steel alloys contain iron, but it resists rust because it also contains a high percentage of chromium which is even more reactive than iron. The chromium in the alloy oxidizes quickly to form a protective layer of chromium oxide on the metal surface which prevents oxygen from reaching the underlying steel.

Use Galvanized Metal

Galvanization is a process used to preserve steel rust-free for many years. In the galvanizing process, a piece of steel is coated with liquid zinc. The zinc protects the steel in three different ways. First, the zinc coating acts as a barrier preventing oxygen and water from reaching the steel. Second, even if the coating is scratched off, the zinc continues to protect nearby areas of the metal through cathodic protection. And third, zinc is highly reactive to oxygen and quickly forms a protective coating of zinc oxide which prevents the iron from further oxidation.

Regular Maintenance

Because rust spreads quickly, it’s important to scrape it off as soon as it appears. Then, scrub with warm water and soap and apply a metal conditioner or other protective coating to prevent further oxidation. If necessary, apply a new coat of paint to the area.

Industrial Metal Supply is the Southland’s largest supplier of all types of metal and metalworking accessories, including rust prevention products.


Carbon Steel vs Stainless Steel

Carbon and stainless steel are both created with percentages of carbon and iron, but their characteristics are fairly distinct. Below, we’ve outlined the benefits and drawbacks of each alloy.

Carbon Steel

This is the most basic form of steel available. A tiny proportion of carbon is added to drastically improve the metal’s hardness, but it also makes the carbon steel less ductile. Typically, the percentage of carbon in this steel is much higher than in stainless steel, and it largely defines how the metal behaves. Any other alloying elements — such as manganese, tungsten, or chromium — have a smaller effect on the carbon steel’s overall properties.

That being said, carbon steel still makes up around 90% of today’s steel production. It can be used to make a wide range of products, such as automobile parts, structural beams, knives, steel wires, and refrigerator parts. The alloy is susceptible to corrosion, so it needs to be galvanized for outdoor use. It’s also not nearly as attractive as stainless steel, with a dull, uninspiring finish. Overall, the higher carbon content increases the metal’s durability, heat distribution, and malleability, but it also lowers its melting point.

Stainless Steel

On a superficial level, stainless steel is an attractive metal, with a lustrous and reflective finish that is easy on the eyes. This is due to the high percentage of chromium (over 10.5%) in the alloy, which changes its appearance and also helps to prevent corrosion. Unlike carbon steel, stainless steel has a chromium oxide coating that protects against rust and stains. Some stainless steel alloys are even resistant to sulfuric or phosphoric acid.

You’ll find stainless steel in countless applications, including handrails, cutlery, razor blades, hot water tanks, medical instruments, jewelry, and many others. During the Art Deco period, stainless steel was hugely influential in creating decorative and structural elements that we revere today. However, stainless steel is heavier than carbon steel and aluminum, with the lowest strength-to-weight ratio. That makes it unsuitable for aviation and other industries where weight is a critical factor.

Overall, stainless steel’s decorative and rust-resistant properties make it the clear winner for many people, but carbon steel is still the preferred metal for manufacturing and construction purposes.